# -*- coding: utf-8 -*-

import cv2
import numpy as np


def nothing(x):
    pass


# 创建一副黑色图像
img = np.zeros((300, 512, 3), np.uint8)

# 设置滑动条组件
cv2.namedWindow('image')
cv2.createTrackbar('R', 'image', 11, 255, nothing)
# cv2.createTrackbar('G', 'image', 0, 255, nothing)
# cv2.createTrackbar('B', 'image', 0, 255, nothing)
# 开关,控制是否启用滑动条
# switch = '0:OFF\n1:ON'
# cv2.createTrackbar(switch, 'image', 0, 1, nothing)

while(1):
    cv2.imshow('image', img)
    k = cv2.waitKey(1) & 0xFF
    if k == 27:
        break

    r = cv2.getTrackbarPos('R', 'image')
    # g = cv2.getTrackbarPos('G', 'image')
    # b = cv2.getTrackbarPos('B', 'image')
    # s = cv2.getTrackbarPos(switch, 'image')
    # if s == 0:
    #     img[:] = 0
    # else:
    img[:] = [0, 0, r]


# 销毁窗口
cv2.destroyAllWindows()
cv2.waitKey(1)
